Long-term effects of a wildfire on the soil nematode communities in the spruce forest ecosystem of High Tatra National Park

This study evaluated the effect of a wildfire on soil nematode communities in the spruce forest ecosystem of the High Tatra Mountains 8 years after the fire. Two plots were established, an intact control plot (REF) and a fire-damaged plot after a windstorm (FIR). A total of 20 representative soil samples were collected; 10 from each site (five in June and five in October). A total of 64 species of nematodes were recorded. The mean number of species 8 years after the fire ranged from 24 to 36 and was always significantly higher in REF than in FIR (P<0.05); with a significantly higher Shannon-Weaver diversity index in REF. Bacterivores were the most abundant trophic group at both sites. Omnivores were more abundant in FIR than in REF, and predators were more abundant in REF. The most abundant species at both sites were Acrobeloides nanus, Aglenchus agricola, Malenchus exiguus and Paratylenchus microdorus. Epidermal or root-hair feeders, mainly Malenchus exiguus, were the most abundant plant-parasitic nematodes at both sites, followed by the ectoparasitic P. microdorus. The migratory endoparasite, Pratylenchus pratensis, was found only in FIR in relatively high numbers, whereas the ectoparasitic species Criconemoides morgensis, Crossonema menzeli and Ogma cobbi occupied only REF. Nematode abundance and species diversity index differed significantly between the disturbed and undisturbed habitats, but ecological and functional indices and metabolic footprints indicate that the soil ecosystem 8 years after the fire had recovered, with moderate levels of nutrient enrichment comparable to those of the control plot.